Hobbing machine



Feb. 18, 1941. ADAMS 2,231,866

HOBBING MACHINE I Filed June 5, 1934 4 Sheets-Sheet 1 I .Arfal/YEYQ Feb 18, 1941. F. H. ADAMS HOBBING MACHINE Filed June 5, 1954 4 Shee'tQ-Sheet z F. H. ADAMS uossme MACHINE Filed June 1954 Feb. 18, 1941.

4 I Sheets-Shet I5 J/vvsrvroz Feb. 18, 1941. F. H. ADAM-S HOBBING MACHINE Filed June 5, 1934 4 Sheets-Sheet 4 Patented Feb. 18, 1941 UNITED STATES- 2,231,866 HOBBING MACHINE Frank 11. Adams, Cleveland Heights, Ohio, assignor to The Cleveland Hobbing Machine Company, Cleveland, Ohio, a corporation of Ohio Application June 5, 1934, Serial No. 729,118

12 Claims.

The present invention relates to machine tools and more particularly to gear cutting machines, especially those commonly called hobbing machines. Herctofore in the art numerous machines have been designed and employed for cutting gears by means of the hobbing principle as well as other principles, but all of these machines have been subject to certain defects and are inadequate to meet the requirements of present day production methods, either as to simplicity of design, rigidity of construction, accuracy of the work produced, or as to floor space required, etc.

An object of the present invention is the provision of a novel machine tool, and more particularly a hobbing machine, which will require a minimum amount of floor space, be simple in design, rigid in construction, and produce accurate work at a high speed with a minimum amount of maintenance and lost' time. 2 The invention resides in certain novel features and details of construction and combination and arrangements of parts, and further objects and advantages thereof will be apparent to those skilled in the art to which it pertains, from the following description of the preferred embodiment thereof described with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a hobbing machine embodying the present invention.

Fig. 2 is a section through approximately the center of the machine with portions in elevation.

Fig. 3 is a section approximately on the line 3-3 of Fig. 2 with portions in elevation.

Fig. 4 is a section on the line 4-4 of Fig. 2 with portions in elevation.

Fig. 5 is a section approximately on the line 5-5 of Fig. 3.

Fig. 6 is a section on the line 6-6 of Fig. 2.

Fig. 7 is a section on the line of Fig. 2.

8 is a developed view of the change gearing shown in Figs. 2, 3 and 5, and

Fig. 9 is a wiring diagram of the electric circuit of the machine.

5 Similar reference characters designate corresponding parts throughout the several views of the drawings.

Referring to the drawings, it will be observed that the machine illustrated is of generally vertical construction, thus enabling the floor space required by the machine to be kept down to a minimum. The bed of the machine, designated in general by the reference character A, which also serves as a sump for the cutting fluid, etc., is made rectangular, permitting a number of machines to be readily gauged close together, synchronized and taken care of by a single operator. The frame of the machine, designated in general by the reference character-B is of heavy channel construction, providing maximum rigidity with 3 minimum weight, and is bolted or otherwise securely fixed to the bed A.

The work head, designated in general by the reference character C, comprises a work head frame I2 slidably supported on vertically spaced 10 ways 13 and i4 formed on the frame B at the top and bottom there'of, respectively. The work head C is held in engagement with the lower ways I 4 by members I5and l6, see Figs. 3 and '7, bolted or otherwise secured to the rear side of the, work 15 head frame l2 and projecting ,to the rear of the overhanging portions of the ways l4. Adjustable tapered gibs l8 and I9 interposed between the members I5 and I6 and the ways [4 are provided for taking up the wear, etc. An adjustable gib supported by a rib 2| 0n the rear of the work head frame l2 and interposed between the rib 2| and the right-hand way ll prevents any side movement of the work head on the ways I4. The upper part of the work head C is maintained in engagement with the ways l3 in a manner similar to that just described with reference to the lower ways I4. Members 22 and 23 bolted to the rear side of the frame l2 extend behind overhanging parts of the ways l3. Tapered gibs interposed between the members 22 and 23 and the ways l3, and a tapered gib 26 interposed between a rib similar to the rib 2| and the'right-hand way are provided for taking up wear, etc., and preventing any play or lost motion between the work head and the frame B. The construction just described provides a rigid support for the work, free from vibration, chatter, etc.

A work spindle 30 rotatably supported in the frame member I2 of the work head 0 by antifriction bearings 3| and 32, see Fig. 2, is provided with a chuck 34 which, together with a tail center 35, supports the work blank W. The tail center 35 is secured in a member 36 adjustably supported in a semi-circular channel formed in the tail stock 31 slidably supported on the ways 38 and 39 formed integral with the work head frame l2. The member 36 is secured in the channel by a bolt 4| projecting through an enlarged aperture in the member 36 and threaded into the tail stock 31. The member 36 and in turn the tail center 35 is adjusted with reference to the tail stock by means of tapered gibs'42 positioned between the member 36 and the tail stock and moved 55 relative to the tail stock by bolts 48 threaded into the latter. Members 44 and 45 bolted to the rear side of the tail stock 81 and projecting to the rear of the overhanging parts of the ways 85 and 39 retain the tail stock in position on the ways. The tail stock 31 is moved along the ways 38 and 39 through the .medium of a rack 49 secured to the work head frame I2, and apinion 52, formed on a member 53, in mesh therewith, and 1 clamped in any desired position by means of a single operating lever 55. The operating lever 55 is pivotally connected to one end of the member 53, and is rotatable about an axis parallel with the ways 88 and 39 to clamp and unclamp the 15 tail stock 31 in position, and about an axis normal thereto to move the tail stock along the ways.

The work spindle 80 is driven at a predetermined speed by an electric motor 50 supported 'on an adjustable platform Si, in a recess in the 20 frame B, through the medium of the followin mechanism. The main drive shaft 54 of the machine is operatively connected to the motor 50 by a flexible drive connection designated in general by the reference character 65, and adjusted 25 by raising or lowering the motor 90 by means of the platform 6|. The rear end of the main drive shaft 64 is rotatably supported in a boss 58 formed integral with the frame B by anti-friction bearings 69, and the front end of the shaft is supported in member 10 fixed to the frame 13, through the medium of a bevel gear II splined thereto, the hub of which is rotatably supported in an aperture I2 in the member I0 by anti-friction bearings 13.

The bevel gear 'II is continuously in mesh with a bevel gear I5 fixed to the upper end of a vertically positioned spline shaft 18 rotatabiy supported in the member I0 by anti-friction bear- 40 ings 11. The lower end of the spline shaft I8 extends into an oil recess 18 in the work head frame I2 and has a splined connection with a bevel gear 80 provided with an elongated hub 8|, rotatabiy supported in a rearwardly extending 45 portion 82 of the work head frame by anti-friction bearings 83. Bevel gear 80 is in mesh with a bevel gear 85 fixed to the rear end of a horizontal shaft 86, rotatabiy supported in the work head frame I2 by anti-friction bearings 81. The 50 front end of the shaft 88 is rotatably supported in a partition 88 in the work head frame by anti-friction bearings 89, and carries a gear 90 fixed thereto. v

The gear 90 is operatively connected to a gear 55 9| fixed to a horizontal shaft 92, through change gears 94 and 95 in mesh with gears 90 and 9I, respectively. The change gears 94 and 85 are rotatably supported on a stud shaft 88 adjustably supported in one of a plurality of 5 T-slots in a bracket 99. The bracket 99 is rotatably supported coaxial with the shaft 88 and is secured in any adjusted position by a nut I00 threaded onto a stud bolt I.0I projecting through an-arcuate slot I02 in the bracket 89. 65 The shaft 92 is operatively connected to the work spindle 30 through a worm and worm wheel I04 and I05, respectively, the former of which is fixed to the shaft 92 and the latter to the spindle 80.

In order to provide means for taking up wear 7 and lost motion between the worm I04 and worm wheel I05 the shaft 92 is rotatably supported in a sleeve member I08 rotatabiy supported in the frame of the work head eccentric with reference to the axis of the shaft 92. The reduced rear 75 end I09 of the member I08 is rotatably supported in a recess 0 in the work head frame I2, and the front end is provided with a flange III rotatabiy supported in the partition 88. The member I08 is rotatedin a manner'to move the worm I04 into the worm wheel I05 by a member is IIkthreaded into an aperture in the partition 88, and provided with a reduced end portion which abuts a flat surface on the flan e III.- The member I08 is'secured in any adjusted position by cap screws I I5 projecting through arcuate 10 slots II5 in the flange III, and having threaded engagement with the partition 89.

The tool head, designated in general by the reference character D, comprises a member I20 slidably supported on horizontal ways I2I formed integral with the frame B intermediate the vertically spaced ways I8 and I4, and a member I22 rotatabiy supported by the member I coaxial with the main drive shaft 54. A tool spindle I25 rotatabiy supported in the member I22 by anti- 20 friction bearings is driven from the main drive shaft 84 through miter gears I28 and I29, the former of which is provided with an elongated hub splined to the front end of the main drive shaft 54 and rotatably supported in a rearwardly 25 extending boss I80 formed integral with the member I22. Miter gear I29 is fixed to one end of a stud shaft I84 rotatably supported in the member I22, the upper end of which carries a spiral pinion I85 in mesh with a spiral gear I88 30 fixed to the tool spindle I25.

A hob arbor I88 secured at its upper end to the tool spindle I25, is rotatably supported in a bracket I88 bolted to the member I22. The

upper end of the tool spindle I25 carries a flywheel I40 fixed thereto. The member I22 is rotatably supported by the member I20 by the engagement of the boss I90 in a cylindrical aperture in the front wall of member I20. Bolts I, the heads of which engage in a circular T-slot 40 I42, secure the member I22 in any adjusted position. The construction just described permits the axis of the hob to'be adjusted about the axis of the main drive shaft, which is normal to the axis of the work spindle. A vernier scale I43 45 permits the hob to be accurately and quickly set at any desired angle.

Movement of the tool head D along the ways I2I to move the hob towards or from the work, is effected by rotation of a shaft I45 rotatabiy 60 supported in the frame B and provided with a worm I48 fixed thereto in mesh with a rack I41 secured to the underside of the member I20. The shaft I45 is provided with a square end to facilitate turning the same and a graduated dial to facilitate setting of the hob. The tool head may be clamped to the way I2I in any adjusted position by bolts I48 if desired. The member I20 has a telescopic connection with the boss-like member I0, which prevents the entrance of chips, I

etc., into the interior of the tool head, while permitting movement thereof along the ways I2I.

The work head C is moved along the vertical ways I8 and I4 to advance the work past the tool through the medium of a lead screw I55, rotatably supported in the work head B, and having threaded engagement with a nut I55 rotatabiy supported in a bracket I51 bolted or otherwise seeured to the base A. Thrust bearings I58 and I59 which take the entire load of the work head are interposed between the lead screw I55 and the work head frame I2, and the nut I58 and the bracket I51, respectively. The lead screw I55 is driven in predetermined timed relation to the rotation of the work and tool spindle, to raise the work head B at the desired feed rate, from a gear I60 fixed to the extreme outer end of the shaft 92. The gear I60 is operatively connected to a gear I6I fixed to the front end of a horizontal shaft I62 through the medium of change gears I63 and I64 in mesh with the gears I60 and I6I respectively, and rotatably supported on a stud shaft I65 adjustably secured in an elongated slot in a bracket I66. The bracket I66 is rotatablysupported coaxial with the shaft I62 and is adapted to be secured in any adjusted position bymeans of a nut I61 threaded onto a bolt I69 secured to the-partition 86, and projecting through an arcuate slot I69 in said bracket. The bracket I66 is also supported by blocks I10 and "I carried by the frame I2 and provided with grooves within which the outer circular edge of the bracket I66 engages. The shaft I62 which is'rotatably supported in the frame I2 and the partition 88 by. anti-friction bearings carries a worm I11 fixed thereto, in mesh with a worm wheel I18 fixed to the upper end of thelead screw I55.

A rapid transverse movement is imparted to the work head B to quickly bring the work up to the cutter, or to quickly return the work head to its starting position by rapidly rotating thenut I56 by means of a reversible motor I supported by the bed A within the frame B. A shaft I8I, rotatably supported in suitable bearings in the bracket I51, is connected to the armature shaft I82 of the motor I80 by a coupling I83, and has fixed thereto a worm I85 in mesh with a worm wheel I86 formed about the circumference of the nut I56. The worm I65 and worm wheel I 86 are of the self-locking type and prevent rotative movement of the nut I56 with reference to the lead screw I55 while the motor I80 is at rest during the feeding movement.

The work head frame I2 is divided into two compartments by the partition 88, both of which compartments are adapted to be filled with oil to the level indicated in Fig. 2 for the lubrication of the various parts housed within the compartments. All the gears etc., in the work head are enclosed within the frame I2, which prevents the entrance of chips and dirt, etc. A telescopic guard I86 prevents the entrance of chips, etc. to the ways I4. Cutting fluid is supplied to the tool by a pump I81 driven from the motor 60 through a flexible drive connection I88. Since the motor 60 is energized only during the cutting operation the cutting fluid is supplied merely as needed. The pump I81, like the motor 60, is supported on an adjustable base in a recess in'the frame B.

The motors 60. and I80 preferably are three phase alternating current motors and the motor I80 is reversible. A wiring diagram of the machine is shown in Fig. 9. The motors are con# trolled by upper and lower limit switches I90 and I9I, respectively, and the start-stop push button switch I92, both the start and stop buttons I93 and I94, respectively, of which are provided with ferrules I95 and I96, respectively, which limit the movement thereof. Both the limit switches and the start-stop push button switch are well known in the art and per se do not form a part of the present invention and maybe of any conventional construction. The start button I93 is normally in the out position, i. e., the position shown in the wiring diagram, but may be set in the neutral position shown in dotted lines by the ferrule I95, and the stop button I94 which is normally closed may be set in the open position by the ferrule I96. The limit switches I90 and I9I are operated and controlled by adjustable stops 200.20I and 202,c'arried by the work head C. The stop 200 engages the arms 203 and 204 ofa. bell crank lever on the limit switch I90 to ac tuate the same, and the stops 2" and 202 engage the arms 206 and 206 of a. bell crank lever on'the limit switch I9I to actuate said switch.

The motor 60 is connected to and from the supply lines L, U, L through the medium of a solenoid operated circuit breaker panel 2I0, the operating solenoid and holding-in circuit of which are indicated as c and 0', respectively. The motor I90 is connected to and from the supply lines through the reversible circuit breaker panel 2| I, the operating solenoids and their respective holding-in circuits of which are desig nated as u,u and d, d. The-reference character u designates the solenoid which closes the circuit to the motor I80 to operate the same in a on opposite sides of the frame.

A precision gauge designated in general by the reference character G is provided for accurately positioning the hob head with reference to the work. The gauge G is of conventional construc- With the machine at rest and a work head in the lower position, the electrical circuit is as shown in the wiring diagram. Assuming that a work blank has been secured in position betweenthe work spindle chuck 34 and the tail center 35 the start button I93 is pressedby theoperator, closing the circuit to the contact relay 2 II which, in turn, closes the circuit to the solenoid u, en-

ergizing the motor I80 to quickly raise the work head and bring the work up to the tool. Upon release of the start button I93 the circuit relay 2 is closed through the holding-in circuit u which is now energized. Thereafter the relay 2 maintains its own circuit. The stop 200 is so positioned that it engages the upstanding arm 203 of the limit switch I90 and moves the contact arm to its lowerposition, see Fig. 9, just prior to the engagement of the work with the hob, opening the circuit to solenoid u and closing the circuit to solenoid 0, through the contacts of relay 2, stopping themotor I80 and-starting the motor 60. The holding-in circuit 0' maintains the circuit to the motor 60 until the work has traveled past the hob and the cutting operation has been completed, at which time the stop 202 engages the arm 206 and trips the limit switch its initial or starting position without interrupt- 

